Electrode support



Patented Aug. 20, 1935 UNITED STATES PATENT OFFICE ELECTBODE SUPPORTwilliam w. Emi mi Jack usb. Sm

MoCullo Bruno, Calif., mignon to Heints Kaufman,

Ltd.,8anl"ranciseo,0alif Nevada .,aeorporationof Our invention relatesto an electrode support particularly adaptable for the positioning andspacing of concentric electrodes in electrical dis'- charge tubes.

Among the objects of our invention are:

To provide a positive spacing and supporting member for concentricelectrodes; to provide a unitary support member upon which a pluralityof grids or other electrodes maybe mounted in electrical discharge tube;to provide a means for 'supporting discharge tube electrodes and toprovide a stepped electrode supporting insulator.

Other objects of our invention will be apparent or will be specificallypointed out in the description forming a part of this speciilcation. butI do not limit myself to the embodiment of my invention hereindescribed. as various forms may be adopted within the scope of theclaims.

In the drawing which delineates a preferred form of support as used in athermionic tube,

Figure 1 is a longitudinal sectional view of a thermionic tube embodyingour invention.

Figures 2 and 3 are sectional views showing various means for lockingmounted electrodes to the insulator.

Figure 4 is a perspective view of a preferred form of grid structuresuch as used in the tube of Figure 1.

'Ihe grid structure shown in Figure 4 is of the type disclosed in ourco-pending application Serial No. 696,974, led November 7, 1933, for aSpace discharge device, and claimed therein.

The electrode support of our invention is particularly adapted for usein tubes known as pentodes wherein there is an anode, a cathode and aplurality of grids therebetween, all of the electrodes preferably beingmounted in concentric relation.

Such a tube is shown in Figure l. An envelope l is provided with are-.entrant stem 2. terminating in a pinch I through which cathode leadsi are sealed. A center cathode support 6 is fused in the pinch betweenthe two cathode leads. A double spiral cathode 1 is held in place aroundthe cathode support 6 by means of an upper slidlng loop 9.

A cylindrical anode l0, surrounding the cathode. is suspended from theupper end of the envelope by anode supports II--Ii preferably four.equally spaced, and sealed to the envelope wall at the end of the tubeopposite the stem. An anode lead l2 passes through the upper end of theenvelope.

Conductive risers Il, cach electrically separate,aresealedthroughtheverticalstemwallandare extended upwardly to positiona stepped insulating block I4. We prefer to use three. or four. of theserisers as shown. to provide the block with a hrm solid support, therisers passing through riser holes Il near the periphery of the block,the block resting on spacer bars i5 below and kept from coming ott byriser bends Il above the block.

The block is roughly of conical shape, and provided with a centralaperture i9 through which u the cathode projects. The upper surface isprovided with a series of steps. each having a -vertical surface 2l andahorizontal surface 2l. The latter surface is roughened or provided withridges 22 in order that the leakage path between the vertical surfacesmay be incr Grids 24 are mounted on each step. These lgrids preferablyare of the case type above referredtoandhaveamarginalheadtowhich cagewires 26 are attached.

We have shown the grids in the instant example as being of circularsection. In that case the vertical surfaces 20 will also be circular,and each grid made of a different diameter in order that the beads mayslide over, and be mounted on the vertical surfaces. The relativediameters and number of grid wires may be varied to suit the requiredcharacteristics of the tube under construction.

As the marginal beads slide over and ilt the vertical surfaces, meansshould be provided so that they will stay in place. Figures 2 and 3 showsuch means.

In Figure 2 the bottom of the vertical surface is slightly under cut toform a circular groove 21. The bottom of the bead may then be spun intothe groove and thus ilrmly attach the grid to the block.

In Figure 3 the vgroove 2l is cut in the center of the surface, and thenthe bead is spun into the depression. Other methods will be apparent,such as the use of separated depressions into which the bead may bepressed at intervals around the surface.

We then prefer to make electrical connection to each grid by drillinglead holes 29 through the block adjacent each grid. and passing leadlink lli through these holes. One end of the link is welded to a grid.the other to a riser. By providing at least as many risers as there aregrids, each grid may be connected to a separate riser, which, beingelectrically separate, will then act not only as supports, but as leadsfor the various electrodes mounted on the block.

Anode. cathode, and grid potentials are, in the construction shown,widely separated. The cathode leads come through the stem pinch, thegrid leads through the stem side wall, and the anode lead through theopposite end o! the tube. Allelements are rigidly supported to resistdeformation, and the grids are positively spaced. The entireconstruction is adapted to glass lathe production methods and is suchthat tubes having substantially constantcharacteristics may be turnedout in quantities.

It is, of course, unnecessary that the grids be of circular section.Whatever the shape, all that is necessary is that the bead slip over andfit the vertical surface, which 4may be readily shaped to receive it.

We claim:

1. In combination with an envelope containing a group of concentricelectrodes including an anode and cathode, a pluralityof said electrodessurrounding said cathode and having marginal beads, a circumferentiallystepped insulator having offset vertical surfaces to which said beadsare applied to position said electrodes in spaced relation, saidvertical faces having depressions therein, and retaining means on saidbeads for engaging said depressions.

2. In combination with an envelope containing a group of concentricelectrodes including a cathode and anode, a plurality of said electrodessurrounding said cathode and having marginal beads. a circumferentiallystepped insulator forming the sole support for said certain electrodesand having oiset vertical surfaces to which said beads are applied inspaced relation, a reentrant stem fused to said envelope. a plurality ofelectrically separate risers fused through the side wall of said stemand terminating in said insulator and supporting it, and separateelectrical link members attached to each of said beads and passingthrough said insulator to contact individual risers.

3. In combination with an envelope containing a group oi.' concentricelectrodes including an anode and cathode, a plurality of saidelectrodes surrounding said cathode and having marginal beads, acircumferentially stepped insulator having oiset vertical surfaces towhich said beads are frictionally applied to position said electrodes inspaced relation.

WILLIAM W. EITEL. JACK MCCULLOUGH.

DISCLAIMER 2,012,038.Wlliam W. Eifel and Jack McGullough, San Bruno,Calif. ELEc'rnonm SUPPORT. Patent dated August 20, 1935. Disclaimer ledOctober 16,

1936, by the assignee, Hein/tz cf: Kaufman, Ltd. Hereby enters thisdiskzlaimer to claim 3 of said Letters Patent,

[Ojal Gazette November 10, 1986.]

